The invention relates to a pneumatic nailing machine in which, even when actual hammering is repeatedly conducted on asphalt roofing shingles or the like, tar adhering to a driver is prevented from sticking to the interior of a nose portion.
When an asphalt roofing shingle which is formed into a sheet-like shape is to be attached to a roof base member, usually, nails are driven via the asphalt roofing shingle into the roof base member.
In a conventional nailing machine, when actual hammering is conducted on asphalt roofing shingles, tar easily sticks to the tip end of a driver, particularly during the hot season. When the driver which has been once driven by compressed air is returned to its initial position, therefore, the tar is pulled into a nose portion. When actual hammering is repeated for a long time period, the tar is stickingly deposited on the inner wall of the nose portion, so that the sliding resistance between the driver and the nose portion is increased. As a result, there may take place a phenomenon in which the returning operation of the piston (the operation of returning the piston to the initial position) is disabled.
Conventionaly, therefore, a nailing machine must be periodically cleaned by gasoline or the like in order to remove tar.
However, the cleaning of a nailing machine must be frequently conducted during the nailing work. Furthermore, the cleaning must be conducted also after the nailing work is ended, because, when a nailing machine is left to stand overnight, tar is hardened and such hardened tar is hardly removed away. It is very cumbersome to clean a nailing machine after the nailing work is ended.